text: Cold black oxide, also known as room temperature black oxide, is applied at a temperature of . It is not an oxide conversion coating, but rather a deposited copper selenide (CuSe) compound. Cold black oxide is convenient for in-house blackening. This coating produces a similar color to the one the oxide conversion does, but tends to rub off easily and offers less abrasion resistance.  The application of oil, wax, or lacquer brings the corrosion resistance up to par with the hot and mid-temperature. Applications for cold black oxide process include tooling and architectural finishing on steel. It is also known as cold bluing.